Online-only Table 1.

Definition of surgical workflow phases and their occurrence in proctocolectomy (P), rectal resection (RR) and sigmoid resection (SR).

ID	Phase name	Phase definition	Present in
0	General preparation and orientation in the abdomen	This phase starts when the laparoscopic camera is first inserted into the abdomen. The phase may include removal of adhesions from the abdominal wall. The phase ends when the first instrument is inserted to manipulate the colon, which marks the beginning of a (colon) mobilization phase.	P, RR, SR
1	Dissection of lymph nodes and blood vessels en bloc	This phase starts when the mesocolon is dissected in order to identify and dissect the inferior mesenteric artery and vein. The phase may include a dissection of the mesocolon after the isolation and division of the vessels in order to harvest the corresponding lymph nodes en bloc.	P, RR, SR
2	Retroperitoneal preparation towards lower pancreatic border	This phase starts with the preparation of the retroperitoneal fat medially to the descending colon toward the lower pancreatic border. The aim of the preparation is a central dissection of the inferior mesenteric vein.	RR
3	Retroperitoneal preparation of duodenum and pancreatic head	This phase starts with the preparation of the retroperitoneal fat medially to the ascending colon towards the duodenum. This phase corresponds to phase 2, but on the site of the ascending colon.	P
4	Mobilization of sigmoid colon and descending colon	This phase starts with the manipulation of the sigmoid or descending colon (usually sigmoid). It comprises mobilization of both sigmoid and descending colon below the splenic flexure. The phase also includes positioning and a check for remaining adhesions or bleedings of the descending colon after mobilization.	P, RR, SR
5	Mobilization of splenic flexure	This phase usually follows phase 4 and starts as soon as the mobilization of the descending colon reaches the splenic flexure in the continuum of the bowel at the lower border of the spleen. During proctocolectomy it includes the retroperitoneal preparation towards the lower border of pancreas (phase 2 in rectal resection)	P, RR, SR
6	Mobilization of transverse colon	This phase starts with the mobilization of the transverse colon and includes the separation of the colon from the greater omentum.	P, RR, SR
7	Mobilization of ascending colon	This phase starts with the mobilization of the ascending colon, either after or before mobilizing the transverse colon. It includes the mobilization of the terminal ileum.	P
8	Dissection and resection of the rectum	This phase starts with the incision of the peritoneal fold towards the small pelvis or with an advancement toward the small pelvis after previous incision of the peritoneum for mobilization of the sigmoid or dissection of the vessels. This phase may include the isolation of the left ureter. For sigmoid resection it may include a circular preparation of the rectosigmoid for resection and stapling of the rectosigmoidal junction only.	P, RR, SR
9	Extra-abdominal preparation of anastomosis	This phase starts when the camera is retracted from the abdomen to perform the mini-laparotomy for extraction of the specimen. For proctocolectomy it includes the preparation of an ileal pouch.	P, RR, SR
10	Intra-abdominal preparation of anastomosis	This phase starts when the camera enters the abdomen after the extra-abdominal preparation of the anastomosis is finished. It includes irrigation and hemostasis (stopping of bleeding) in the small pelvis and other places in the abdomen after resection and after extra-abdominal preparation of the anastomosis. It may also include additional mobilisation of ileum, colon or (in sigmoid resection) remaining rectum to reduce tension on the anastomosis.	P, RR, SR
11	Creation of stoma	This phase starts when small bowel length is estimated beginning from the terminal ileum in order to identify the bowel loop for the stoma. The phase may include an extra-abdominal part for positioning of the stoma and afterwards a laparoscopic inspection for torquation of bowel. Also, the extra-abdominal suturing of the stoma may take place before final laparoscopic inspection or afterwards.	P, RR
12	Finalization of operation	This phase starts with and includes insertion of drains and / or irrigation and final check for bleedings. The phase may include inspection of small bowel for lesions and their suturing.	P, RR, SR
13	Exception	This phase comprises some unique phases that occurred exceptionally and unexpectedly during the annotation of the videos, due to the complexity of colorectal procedures. This included the closing of a bladder lesion, excisions of liver tissue for biopsy, appendectomy, a second resection of the rectum during the same procedure, resection of a mesocolonic cyst, cholecystectomy, elaborate hemostasis of splenic bleeding and a suturing of the abdominal wall due to bleeding from a trocar incision.	P, RR, SR